Why are the leaves green in spring and summer, but yellow and red in autumn?

The cause of the discoloration of the leaves is related to the chemical inside it – chlorophyll.

Carotenoids, anthocyanins.

and so on. It is also the result of the comprehensive effect of external temperature, temperature difference, light and other factors. In spring and summer, chlorophyll synthesis is greater than decomposition, and the leaves are green; Autumn is coming, the temperature drops, and the amount of chlorophyll synthesized is less than the amount of chlorophyll that is decomposed.

When its content decreases, other chemical pigments appear. If carotenoids (lutein.

and carotene) in high proportions, the leaves will appear yellow or orange; In late autumn, because of the low temperature, the ability of the leaves to transport sugar and water and glucose is weakened.

The concentration of the cells is constantly increasing, while the increase in soluble sugars makes the cells acidic.

Under acidic conditions, anthocyanins turn red, as do leaves with a high proportion of anthocyanins. Of course, leaf discoloration is a complex process. When the cold air is strong, the temperature drops, causing low temperatures.

After that, the weather was sunny and the temperature difference was large. Such meteorological conditions promote the rapid conversion of chlorophyll into carotenoids and anthocyanins in the leaves. The external change is that the color of the leaves gradually changes from green to yellow, orange, red.

You should be familiar with chlorophyll, because almost all natural plant leaves contain chlorophyll. Through chlorophyll, the leaves absorb the energy needed by the sun and from water and carbon dioxide.

nutrients are extracted. Chlorophyll occupies a very important place in plants. Chlorophyll is green and is the main chemical hidden in the leaves. In spring and summer, the color of the leaves is green.

With the arrival of autumn, the days become shorter and the plants photosynthesize.

It becomes less, so the leaves contain very little chlorophyll and will slowly change to other colors. Colors of many plants, fruits, vegetables, etc. All are related to anthocyanins, which are water-soluble natural pigments. Anthocyanins.

The color is affected by a variety of factors, such as low temperature, lack of oxygen, etc., which can reduce the formation of anthocyanins. Anthocyanins can absorb green light.

Blu-ray, etc. In autumn, anthocyanins increase rapidly, showing more vibrant colors such as scarlet, purple, etc. Because the proportions of the leaves are different, the color will also be different. In fact, there are many reasons for leaf discoloration, but the above three reasons are the main ones.

Leaf discoloration is also related to temperature, humidity, soil, pH, but light is important. Autumn is much less sunny than summer, so the leaves turn from green to yellow. As winter approaches, many changes take place in the plants.

Temperatures drop and daylight hours are shortened. The green tones of the leaves have disappeared, and other colors covered in chlorophyll can now be seen, replaced by the stunning splendor of autumn. Temperature can also affect the color of autumn leaves.

The higher the temperature, the brighter the color, and vice versa. Some trees shed their leaves, while others do not. In the north, winters are colder, forcing most tree species to lose their leaves, with a few exceptions.

There are many chlorophylls in the leaves of plants and because of the presence of chlorophyll, the leaves of the plants we see are green. Chlorophyll is active when the temperature is right, so the leaves of the plant turn green during the warm spring and summer. However, in leaves, there are other pigments besides chlorophyll.

If the chlorophyll disappears, these chlorophylls will show their original color. So the leaves turn yellow or red. In summer, the leaves remain green for a long time because new chlorophyll is constantly being produced to replace the old ones that have faded.

In autumn, the leaves are unable to withstand the effects of low temperatures, and the ability to produce new chlorophyll gradually disappears, and the green color gradually fades, while the more stable carotenoids remain there, so the leaves turn yellow. There are also leaves that produce anthocyanins that turn red.

The leaves are rich in chlorophyll, and in spring and summer, the climate is relatively moderate, so it will have a green color. In the fall, when chlorophyll is broken down until it disappears, lutein and carotene are revealed, so the color turns yellow and red.

In spring and summer, the days are relatively long, so chlorophyll production is more green, and it changes after autumn.

When drinking drinks in life, parents often say that drinking less pigmented is not good for the body.

So the leaves are colored, is there also pigment in the leaves?

Pigments do exist in leaves, such as chlorophyll (chlorophyll a and chlorophyll b), as well as lutein, carotene, anthocyanins, and so on. The presence of these pigments is the fundamental reason why the leaves are able to be colorful. In addition, the pigment of the vacuole in the mesophyll cells of the leaves (the color of the leaves of non-green plants is determined by the pigment in the vacuole) can also determine the color of the leaves.

The pigment content of leaves changes with the external environment, especially sensitive to temperature, humidity, light and other conditions. This is also the reason why the leaves of the trees will have different colors depending on the season.

Autumn has arrived, the leaves have changed from green to yellow, why do the leaves change color?

Because in spring and summer, the chlorophyll content in the leaves is much larger than the content of lutein and carotene, and the chlorophyll role is prominent, and the leaves are green; When the temperature drops in autumn, the light time is shortened, which affects the absorption capacity of the root system and the photosynthesis of leaves, so it cannot meet the growth and development of trees. When the temperature drops and the air is dry, the water in the leaves evaporates quickly, but the ability of the roots to absorb water has been greatly reduced, and the water and nutrients are insufficient. In order to survive, the tree generates an isolation layer at the junction of the petiole and the leaf stem, and the leaves are cut off from the water supply, and the chlorophyll is destroyed due to the low temperature, so the lutein begins to be active.

Chlorophyll synthesis requires higher temperatures and stronger light, and chlorophyll synthesis is hindered. In addition, chlorophyll is characterized by instability and easy decomposition when exposed to light. Therefore, the proportion of chlorophyll in leaves decreases in autumn, and the role of lutein and carotenoids is highlighted.

At this time, the leaves will appear red or yellow.

This is the reason why the leaves of trees turn yellow in autumn.

Hope mine can help you.

In autumn, the temperature decreases, and the chlorophyll in the leaves slowly decreases, which is why they turn yellow.

This is because in autumn, when the weather is colder and no chlorophyll is formed, it changes color.

Because trees change according to the climate, according to the change of seasons, and there is chlorophyll in the leaves.

Turning yellow may mean that such leaves have been turned yellow by such hot air. This is very yellow, and it is also very good-looking.

In autumn, the outside temperature slowly decreases, and the branches no longer transport nutrients to the leaves, so the color of the leaves slowly turns yellow.

Why do the leaves turn yellow in autumn?

Trees with red leaves: maple, coxagulus, persimmon, torch.

Trees with yellowing leaves: poplars, willows, locust trees, elms, tsubaki trees.

1. Maple trees. Maple trees are tall trees that can reach heights of more than 29 meters and a crown width of up to 16 meters. It blooms from April to May and bears fruit from September to October. As the tree ages, the canopy gradually opens up and is rounded.

The shoots are brownish-red to brown with small holes, and the branches are black-brown or gray in winter. Maple leaves have brilliant colors and unique shapes, and can be used to make bookmarks, specimens, etc. In autumn it turns fiery red and when it falls to the ground, it turns crimson red.

Second, poplars. The naming of poplar trees is a complex issue, and there is confusion about the naming method due to the disagreement of scholars. Nowadays, some poplar varieties that have been widely cultivated and popularized do not have a correct and unified name, and some poplar varieties cultivated in various regions are even more confusing.

The reddening of leaves is mainly caused by anthocyanins, which are usually produced by the leaves in autumn. Some scientists believe that pigments such as anthocyanins act as antioxidants to help trees withstand harsh environments.

There are also scientists who believe that these pigments can increase the temperature of the leaves, which can help the trees resist cold. William Oak, a scientist at Montana State University in the United States, suggested a few years ago that anthocyanins may act as a protective effect on sunscreens, preventing leaves from falling prematurely due to sun damage in the fall, allowing trees to draw more nutrients from their leaves.

The trees that turn red are: pentagonal maple, maple, cochine, persimmon, torch, etc.

There are too many yellowing trees, such as: poplars, willows, locust trees, elms, tsubaki trees, etc.

Why are the leaves green in spring and summer, but yellow and red in autumn?

Dear I am happy to answer for you, and the answer to your question is: why are the leaves green in spring and summer, and turn yellow and red in autumn? In fact, most of the leaves are green because the leaves contain a lot of chlorophyll.

But in addition to chlorophyll, leaves contain small amounts of anthocyanins (red or purple), lutein (yellow), and carrots. The color of the leaves is due to the different content and proportion of these pigments. In spring and summer, chlorophyll is much more abundant in the leaves than in other chromospins, so the leaves take on the green color of chlorophyll and the color of the other pigments is not visible.

When autumn comes, the chlorophyll content in the leaves gradually decreases, and the colors of other pigments will gradually appear on the leaf surface, so the leaves will show yellow, red and other colors.

Why, when the leaves of plants turn from green to yellow or red?

The degradation of chlorophyllum spike lead sun is excited, revealing lutein and carotene, which are the main reasons for the yellowing of leaves. Synthetic anthocyanins. The frost leaves are red in February, and this is not a simple metaphor.

Some frost leaves really have the same ingredients as flowers, that is, anthocyanins. Anthocyanins are actually a kind of pigment that plays a protective role in guessing the chain, because at low temperatures, too much sunlight will damage chloroplasts, so plants need to synthesize some anthocyanins to block part of the light, which is the reason for red leaves. ”